I almost never downvote except for posts that are egregiously outside of HN community standards, and certainly wouldn't downvote you here. But your comment does

I almost never downvote except for posts that are egregiously outside of HN community standards, and certainly wouldn't downvote you here. But your comment does seems pretty irrelevant to the issue of their IPO (for the record, I loathe Dropbox for political & technical reasons not pertinent here). If you're getting downvotes, it may not be because people disagree with you, but they might consider you're adding noise (as am I by commenting on your noise, admittedly)?